The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Jan G. Jakobsson - One of the best experts on this subject based on the ideXlab platform.
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the impact of Fresh Gas Flow on wash in wash out time and Gas consumption for sevoflurane and desflurane comparing two anaesthesia machines a test lung study
F1000Research, 2017Co-Authors: Fredrik Leijonhufvud, Fredrik Joneby, Jan G. JakobssonAbstract:Low-Flow anaesthesia is considered beneficial for the patient and the environment, and it is cost reducing due to reduced anaesthetic Gas consumption. An initial high-Flow to saturate the circle system ( wash-in ) is desirable from a clinical point of view. We measured the wash-in and wash-out times (time to saturate and to eliminate the anaesthetic agent, AA), for sevoflurane and desflurane, in a test-lung with fixed 3 MAC vaporizer setting at different Fresh Gas Flow (FGF) and calculated the consumption of AA. We tried to find an optimal Flow rate for speed and Gas consumption, comparing two anaesthesia machines (AMs): Aisys and Flow-i. Time to reach 1 minimal alveolar concentration (MAC) (wash-in) decreased (p<0.05) at higher Flow rates (1 – 2 – 4) but plateaued at 4-4.8 l/min. The consumption of AA was at its lowest around 4-4.8 l/min (optimal Flow) for all but the Aisys /desflurane group. Wash-out times decreased as FGF increased, until reaching plateau at FGF of 4-6 l/min. Aisys had generally shorter wash-in times at Flow rates < 4 l/min as well as lower consumption of AA. At higher Flow rates there were little difference between the AMs. The “optimal FGF” for wash-out, elimination of Gas from the test-lung and circle system, plateaued with no increase in speed beyond 6 l/min. A Fresh Gas Flow of 4 l/min. seems “optimal” taking speed to reach a 1 MAC ET and Gas consumption into account during wash-in with a fixed 3 MAC vaporizer setting, and increasing Fresh Gas Flow beyond 6 l/min does not seem to confirm major benefit during wash-out.
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The impact of Fresh Gas Flow on wash-in, wash-out time and Gas consumption for sevoflurane and desflurane, comparing two anaesthesia machines, a test-lung study.
F1000Research, 2017Co-Authors: Fredrik Leijonhufvud, Fredrik Joneby, Jan G. JakobssonAbstract:Low-Flow anaesthesia is considered beneficial for the patient and the environment, and it is cost reducing due to reduced anaesthetic Gas consumption. An initial high-Flow to saturate the circle system ( wash-in ) is desirable from a clinical point of view. We measured the wash-in and wash-out times (time to saturate and to eliminate the anaesthetic agent, AA), for sevoflurane and desflurane, in a test-lung with fixed 3 MAC vaporizer setting at different Fresh Gas Flow (FGF) and calculated the consumption of AA. We tried to find an optimal Flow rate for speed and Gas consumption, comparing two anaesthesia machines (AMs): Aisys and Flow-i. Time to reach 1 minimal alveolar concentration (MAC) (wash-in) decreased (p
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Brief review: theory and practice of minimal Fresh Gas Flow anesthesia.
Canadian Journal of Anaesthesia-journal Canadien D Anesthesie, 2012Co-Authors: Metha Brattwall, Margareta Warren-stomberg, Fredrik Hesselvik, Jan G. JakobssonAbstract:The aim of this brief review is to provide an update on the theory regarding minimal Fresh Gas Flow techniques for inhaled general anesthesia. The article also includes an update and discussion of the practical aspects associated with minimal-Flow anesthesia, including the advantages, potential limitations, and safety considerations of this important anesthetic technique. Reducing the Fresh Gas Flow to
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brief review theory and practice of minimal Fresh Gas Flow anesthesia
Canadian Journal of Anaesthesia-journal Canadien D Anesthesie, 2012Co-Authors: Metha Brattwall, Fredrik Hesselvik, Margareta Warrenstomberg, Jan G. JakobssonAbstract:The aim of this brief review is to provide an update on the theory regarding minimal Fresh Gas Flow techniques for inhaled general anesthesia. The article also includes an update and discussion of the practical aspects associated with minimal-Flow anesthesia, including the advantages, potential limitations, and safety considerations of this important anesthetic technique. Reducing the Fresh Gas Flow to < 1 L·min−1 during maintenance of anesthesia is associated with several benefits. Enhanced preservation of temperature and humidity, cost savings through more efficient utilization of inhaled anesthetics, and environmental considerations are three key reasons to implement minimal-Flow and closed-circuit anesthesia, although potential risks are hypoxic Gas mixtures and inadequate depth of anesthesia. The basic elements of the related pharmacology need to be considered, especially pharmacokinetics of the inhaled anesthetics. The third-generation inhaled anesthetics, sevoflurane and desflurane, have low blood and low tissue solubility, which facilitates rapid equilibration between the alveolar and effect site (brain) concentrations and makes them ideally suited for low-Flow techniques. The use of modern anesthetic machines designed for minimal-Flow techniques, leak-free circle systems, highly efficient CO2 absorbers, and the common practice of utilizing on-line real-time multi-Gas monitor, including essential alarm systems, allow for safe and cost-effective minimal-Flow techniques during maintenance of anesthesia. The introduction of new anesthetic machines with built-in closed-loop algorithms for the automatic control of inspired oxygen and end-tidal anesthetic concentration will further enhance the feasibility of minimal-Flow techniques. With our modern anesthesia machines, reducing the Fresh Gas Flow of oxygen to 0.3-0.5 L·min−1 and using third-generation inhaled anesthetics provide a reassuringly safe anesthetic technique. This environmentally friendly practice can easily be implemented for elective anesthesia; furthermore, it will facilitate cost savings and improve temperature homeostasis.
Hye Won Shin - One of the best experts on this subject based on the ideXlab platform.
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the effect of Fresh Gas Flow rate and type of anesthesia machine on time to reach target sevoflurane concentration
BMC Anesthesiology, 2017Co-Authors: Hye Won Shin, Hae Na Yu, Ji Yong ParkAbstract:Background Anesthesia machines have been developed by the application of new technology for rapid and easier control of anesthetic concentration. In this study, we used a test lung to investigate whether the time taken to reach the target sevoflurane concentration varies with the rate of Fresh Gas Flow (FGF) and type of anesthesia machine (AM).
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The effect of Fresh Gas Flow rate and type of anesthesia machine on time to reach target sevoflurane concentration.
BMC Anesthesiology, 2017Co-Authors: Hye Won Shin, Hae Na Yu, Ji Yong ParkAbstract:Anesthesia machines have been developed by the application of new technology for rapid and easier control of anesthetic concentration. In this study, we used a test lung to investigate whether the time taken to reach the target sevoflurane concentration varies with the rate of Fresh Gas Flow (FGF) and type of anesthesia machine (AM). We measured the times taken to reach the target sevoflurane concentration (2 minimum alveolar concentration = 4%) at variable rates of FGF (0.5, 1, or 3 L/min) and different types of AM (Primus®, Perseus®, and Zeus® [Zeus®-F; Zeus® Fresh Gas mode, Zeus®-A; Zeus® auto-mode]). Concomitant ventilation was supplied using 100% O2. The AMs were connected to a test lung. A sevoflurane vaporizer setting of 6% was used in Primus®, Perseus®, and Zeus®-F; a target end-tidal setting of 4% was used in Zeus®-A (from a vaporizer setting of 0%). The time taken to reach the target concentration was measured in every group. When the same AM was used (Primus®, Perseus®, or Zeus®-F), the times to target concentration shortened as the FGF rate increased (P
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The effect of Fresh Gas Flow rate and type of anesthesia machine on time to reach target sevoflurane concentration
BMC Anesthesiology, 2017Co-Authors: Hye Won Shin, Hae Na Yu, Ji Yong ParkAbstract:Background Anesthesia machines have been developed by the application of new technology for rapid and easier control of anesthetic concentration. In this study, we used a test lung to investigate whether the time taken to reach the target sevoflurane concentration varies with the rate of Fresh Gas Flow (FGF) and type of anesthesia machine (AM). Methods We measured the times taken to reach the target sevoflurane concentration (2 minimum alveolar concentration = 4%) at variable rates of FGF (0.5, 1, or 3 L/min) and different types of AM (Primus^®, Perseus^®, and Zeus^® [Zeus^®-F; Zeus^® Fresh Gas mode, Zeus^®-A; Zeus^® auto-mode]). Concomitant ventilation was supplied using 100% O_2. The AMs were connected to a test lung. A sevoflurane vaporizer setting of 6% was used in Primus^®, Perseus^®, and Zeus^®-F; a target end-tidal setting of 4% was used in Zeus^®-A (from a vaporizer setting of 0%). The time taken to reach the target concentration was measured in every group. Results When the same AM was used (Primus^®, Perseus^®, or Zeus^®-F), the times to target concentration shortened as the FGF rate increased ( P
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the effect of Fresh Gas Flow rate and type of anesthesia machine on time to reach target sevoflurane concentration
BMC Anesthesiology, 2017Co-Authors: Hye Won Shin, Hae Na Yu, Ji Yong ParkAbstract:Anesthesia machines have been developed by the application of new technology for rapid and easier control of anesthetic concentration. In this study, we used a test lung to investigate whether the time taken to reach the target sevoflurane concentration varies with the rate of Fresh Gas Flow (FGF) and type of anesthesia machine (AM). We measured the times taken to reach the target sevoflurane concentration (2 minimum alveolar concentration = 4%) at variable rates of FGF (0.5, 1, or 3 L/min) and different types of AM (Primus®, Perseus®, and Zeus® [Zeus®-F; Zeus® Fresh Gas mode, Zeus®-A; Zeus® auto-mode]). Concomitant ventilation was supplied using 100% O2. The AMs were connected to a test lung. A sevoflurane vaporizer setting of 6% was used in Primus®, Perseus®, and Zeus®-F; a target end-tidal setting of 4% was used in Zeus®-A (from a vaporizer setting of 0%). The time taken to reach the target concentration was measured in every group. When the same AM was used (Primus®, Perseus®, or Zeus®-F), the times to target concentration shortened as the FGF rate increased (P < 0.05). Conversely, when the same FGF rate was used, but with different AMs, the time to target concentration was shortest in Perseus®, followed by Primus®, and finally by Zeus®-F (P < 0.05). With regards to both modes of Zeus®, at FGF rates of 0.5 and 1 L/min, the time to target concentration was shorter in Zeus®-A than in Zeus®-F; however, the time was longer in Zeus®-A than in Zeus®-F at FGF rate of 3 L/min (P < 0.05). Shorter times taken to reach the target concentration were associated with high FGF rates, smaller internal volume of the AM, proximity of the Fresh Gas inlets to patients, absence of a decoupling system, and use of blower-driven ventilators in AM.
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effect of Fresh Gas Flow on isoflurane concentrations during low Flow anaesthesia
Journal of International Medical Research, 2005Co-Authors: Jewel Park, Moon Seok Chang, Hye Won ShinAbstract:The effect of Fresh Gas Flow (FGF) on isoflurane concentrations at given vaporizer settings during low-Flow anaesthesia was investigated. Ninety patients (American Society of Anaesthesiologists physical status I or II) were randomly allocated to three groups (FGF 1 l/min, FGF 2 l/min and FGF 4 l/min). Anaesthesia was maintained for 10 min with vaporizer setting isoflurane 2 vol% and FGF 4 l/min for full-tissue anaesthetic uptake in a semi-closed circle system. Low-Flow anaesthesia was maintained for 20 min with end-tidal isoflurane 1.5 vol% and FGF 2 l/min. FGF was then changed to FGF 1 l/min, FGF 2 l/min or FGF 4 l/min. Measurements during the 20-min period showed that inspired and end-tidal isoflurane concentrations decreased in the FGF 1-l/min group but increased in the FGF 4-l/min group compared with baseline values. No haemodynamic changes were observed. Monitoring of anaesthetic concentrations and appropriate control of vaporizer settings are necessary during low-Flow anaesthesia.
Richard A French - One of the best experts on this subject based on the ideXlab platform.
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the effect of Fresh Gas Flow during induction of anaesthesia on sevoflurane usage a quality improvement study
Anaesthesia, 2019Co-Authors: R R Kennedy, Richard A French, G Vesto, J Hanrahan, J PageAbstract:: Reducing Fresh Gas Flow during inhalational anaesthesia results in cost savings and decreases environmental impact. We are interested in the influence of Fresh Gas Flow on the early (induction) phase of overall Fresh Gas Flow and vapour consumption. This stage is often excluded in studies of Fresh Gas Flow. Data were collected from 3199 sevoflurane anaesthetics over an 11-month period in four operating theatres. We determined Fresh Gas Flow at different stages of anaesthesia, and developed an explanatory model for the influence of the 'induction' period. Following a three-month collection of baseline data we emphasised the importance of the early phase to our department repeatedly over a two-week period. We explored the relationship between Fresh Gas Flow and total vapour usage, and used a simple mathematical model to explore the effect of changes in the Fresh Gas Flow and duration of the 'induction' phase. Mean Fresh Gas Flow was 1.15 l.min-1 in the baseline period and 0.91 l.min-1 in the two months following our educational effort (p = 0.0005). In the following six months, mean Fresh Gas Flow was 1.17 l.min-1 (p = 0.7726 compared with baseline). These results were driven by changes in both Fresh Gas Flow and duration of the initial high-Flow period. We found some correlation (R2 = 0.85) between overall Fresh Gas Flow and vapour consumption; a 1 l.min-1 increase in Fresh Gas Flow consumes an additional 18 ml.hr-1 of liquid sevoflurane. This preliminary study demonstrates that an episode of high Fresh Gas Flow at the start of anaesthesia has a large and modifiable effect on overall Fresh Gas Flow and vapour consumption. We also confirmed the linear relationship between Fresh Gas Flow and vapour usage.
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changing patterns in anesthetic Fresh Gas Flow rates over 5 years in a teaching hospital
Anesthesia & Analgesia, 2008Co-Authors: R R Kennedy, Richard A FrenchAbstract:BACKGROUND: Reducing anesthetic Fresh Gas Flows can reduce volatile anesthetic consumption without affecting drug delivery to the patient. Delivery systems with electronic Flow transducers permit the simple and accurate collection of Fresh Gas Flow information. In a 2001 audit of Fresh Gas Flow, we found little response to interventions designed to foster more efficient use of Fresh Gas. We compared current practice with our earlier results. METHODS: Flow data were collected in areas with a mix of general and acute surgery in March and November 2001, and again during 2006, by recording directly from the Datex ADU to a computer every 10 s. We extracted the distribution of Flow rates when a volatile anesthetic was being administered. Data collection in March 2001 and 2006 was not advertised. RESULTS: In 2001, the mean Flow rates were 1.95 and 2.1 L/min with a median Flow of 1.5 L/min. In 2006, the mean was 1.27 and the median in the range 0.5-1.0 L/min. Isoflurane use decreased from 47% in 2001 to 4% in 2006. CONCLUSIONS: Fresh Gas Flows used in our department have decreased by 35% over 4 years. Although the absolute change in Flow rate is not large, this represents potential annual savings of more than $US130,000. This occurred without specific initiatives, suggesting an evolution in practice towards lower Fresh Gas Flow. Improvements in equipment and monitoring, including a locally developed system, which displays forward predictions of end-tidal and effect-site vapor concentrations, may be factors in this change.
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an audit of anaesthetic Fresh Gas Flow rates and volatile anaesthetic use in a teaching hospital
The New Zealand Medical Journal, 2003Co-Authors: R R Kennedy, Richard A FrenchAbstract:AIM: The large number of anaesthetics administered means that the total cost to a hospital of inhalational anaesthetic agent such as isoflurane or sevoflurane can be considerable. The total anaesthetic Gas Flow is a major determinant of the use of these agents. Modern anaesthetic machines and monitoring facilitate reduced Gas Flows, which can significantly reduce wastage of these anaesthetic agents. The purpose of this study was to audit Gas Flow rates and volatile anaesthetic use. METHODS: We audited Gas Flows and choice of anaesthetic agent over two one-month periods in one theatre at Christchurch Hospital. Data were collected directly from the anaesthetic machine using a computer. The second study period was clearly advised and followed widespread discussion of results from the first study period. RESULTS: Average Fresh-Gas Flow was approximately 2 l/min (Month 1 = 2.0 l/min, Month 2 = 2.1 l/min). Use of the more expensive agent, sevoflurane, increased but Gas Flows with this agent decreased. CONCLUSIONS: Given the low Flows used, the small difference between study periods was not surprising. The Gas Flows recorded represent responsible use of anaesthetic agents and are at least as good as Flows achieved in previous studies that employed various methods to encourage their reduction.
R R Kennedy - One of the best experts on this subject based on the ideXlab platform.
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the effect of Fresh Gas Flow during induction of anaesthesia on sevoflurane usage a quality improvement study
Anaesthesia, 2019Co-Authors: R R Kennedy, Richard A French, G Vesto, J Hanrahan, J PageAbstract:: Reducing Fresh Gas Flow during inhalational anaesthesia results in cost savings and decreases environmental impact. We are interested in the influence of Fresh Gas Flow on the early (induction) phase of overall Fresh Gas Flow and vapour consumption. This stage is often excluded in studies of Fresh Gas Flow. Data were collected from 3199 sevoflurane anaesthetics over an 11-month period in four operating theatres. We determined Fresh Gas Flow at different stages of anaesthesia, and developed an explanatory model for the influence of the 'induction' period. Following a three-month collection of baseline data we emphasised the importance of the early phase to our department repeatedly over a two-week period. We explored the relationship between Fresh Gas Flow and total vapour usage, and used a simple mathematical model to explore the effect of changes in the Fresh Gas Flow and duration of the 'induction' phase. Mean Fresh Gas Flow was 1.15 l.min-1 in the baseline period and 0.91 l.min-1 in the two months following our educational effort (p = 0.0005). In the following six months, mean Fresh Gas Flow was 1.17 l.min-1 (p = 0.7726 compared with baseline). These results were driven by changes in both Fresh Gas Flow and duration of the initial high-Flow period. We found some correlation (R2 = 0.85) between overall Fresh Gas Flow and vapour consumption; a 1 l.min-1 increase in Fresh Gas Flow consumes an additional 18 ml.hr-1 of liquid sevoflurane. This preliminary study demonstrates that an episode of high Fresh Gas Flow at the start of anaesthesia has a large and modifiable effect on overall Fresh Gas Flow and vapour consumption. We also confirmed the linear relationship between Fresh Gas Flow and vapour usage.
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changing patterns in anesthetic Fresh Gas Flow rates over 5 years in a teaching hospital
Anesthesia & Analgesia, 2008Co-Authors: R R Kennedy, Richard A FrenchAbstract:BACKGROUND: Reducing anesthetic Fresh Gas Flows can reduce volatile anesthetic consumption without affecting drug delivery to the patient. Delivery systems with electronic Flow transducers permit the simple and accurate collection of Fresh Gas Flow information. In a 2001 audit of Fresh Gas Flow, we found little response to interventions designed to foster more efficient use of Fresh Gas. We compared current practice with our earlier results. METHODS: Flow data were collected in areas with a mix of general and acute surgery in March and November 2001, and again during 2006, by recording directly from the Datex ADU to a computer every 10 s. We extracted the distribution of Flow rates when a volatile anesthetic was being administered. Data collection in March 2001 and 2006 was not advertised. RESULTS: In 2001, the mean Flow rates were 1.95 and 2.1 L/min with a median Flow of 1.5 L/min. In 2006, the mean was 1.27 and the median in the range 0.5-1.0 L/min. Isoflurane use decreased from 47% in 2001 to 4% in 2006. CONCLUSIONS: Fresh Gas Flows used in our department have decreased by 35% over 4 years. Although the absolute change in Flow rate is not large, this represents potential annual savings of more than $US130,000. This occurred without specific initiatives, suggesting an evolution in practice towards lower Fresh Gas Flow. Improvements in equipment and monitoring, including a locally developed system, which displays forward predictions of end-tidal and effect-site vapor concentrations, may be factors in this change.
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an audit of anaesthetic Fresh Gas Flow rates and volatile anaesthetic use in a teaching hospital
The New Zealand Medical Journal, 2003Co-Authors: R R Kennedy, Richard A FrenchAbstract:AIM: The large number of anaesthetics administered means that the total cost to a hospital of inhalational anaesthetic agent such as isoflurane or sevoflurane can be considerable. The total anaesthetic Gas Flow is a major determinant of the use of these agents. Modern anaesthetic machines and monitoring facilitate reduced Gas Flows, which can significantly reduce wastage of these anaesthetic agents. The purpose of this study was to audit Gas Flow rates and volatile anaesthetic use. METHODS: We audited Gas Flows and choice of anaesthetic agent over two one-month periods in one theatre at Christchurch Hospital. Data were collected directly from the anaesthetic machine using a computer. The second study period was clearly advised and followed widespread discussion of results from the first study period. RESULTS: Average Fresh-Gas Flow was approximately 2 l/min (Month 1 = 2.0 l/min, Month 2 = 2.1 l/min). Use of the more expensive agent, sevoflurane, increased but Gas Flows with this agent decreased. CONCLUSIONS: Given the low Flows used, the small difference between study periods was not surprising. The Gas Flows recorded represent responsible use of anaesthetic agents and are at least as good as Flows achieved in previous studies that employed various methods to encourage their reduction.
Duangthida Nonlhaopol - One of the best experts on this subject based on the ideXlab platform.
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comparative study of minimal Fresh Gas Flow used in lack plus and lack s circuit in spontaneously breathing anesthetized adults
Medical Devices : Evidence and Research, 2016Co-Authors: Sunchai Theerapongpakdee, Thepakorn Sathitkarnmanee, Sirirat Tribuddharat, Siwalai Sucher, Maneerat Thananun, Duangthida NonlhaopolAbstract:BACKGROUND: The Lack's circuit is a co-axial Mapleson A breathing system commonly used in spontaneously breathing anesthetized adults but still requires high Fresh Gas Flow (FGF). The Lack-Plus circuit was invented with the advantage of lower FGF requirement. The authors compared the Lack-Plus and Lack's circuit for the minimal FGF requirement with no rebreathing in spontaneously breathing anesthetized adults. METHODS: This was a randomized crossover study. We enrolled 24 adult patients undergoing supine elective surgery, with a body mass index ≤30 kg/m2 and an American Society of Anesthesiologists physical status I-II. They were randomly allocated to group 1 (LP-L) starting with Lack-Plus then switching to Lack's circuit or group 2 (L-LP) (with the reverse pattern). After induction and intubation, anesthesia was maintained with 50% N2O/O2 and desflurane (4%-6%) plus fentanyl titration to maintain an optimal respiratory rate between 10 and 16/min. Starting with the first circuit, all the patients were spontaneously breathing with a FGF of 4 L/min for 10 min, gradually decreased by 0.5 L/min every 5 min until FGF was 2.5 L/min. End-tidal CO2, inspired minimum CO2 (ImCO2), mean arterial pressure, and oxygen saturation were recorded until rebreathing (ImCO2 >0 mmHg) occurred. The alternate anesthesia breathing circuit was used and the measurements were repeated. RESULTS: The respective minimal FGF at the point of rebreathing for the Lack-Plus and Lack's circuit was 2.7±0.8 and 3.3±0.5 L/min, respectively, p<0.001. At an FGF of 2.5 L/min, the respective ImCO2 was 1.5±2.0 and 4.2±2.6 mmHg, respectively, p<0.001. CONCLUSION: The Lack-Plus circuit can be used safely and effectively, and it requires less FGF than Lack's circuit in spontaneously breathing anesthetized adults.
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Comparative study of minimal Fresh Gas Flow used in Lack-Plus and Lack's circuit in spontaneously breathing anesthetized adults.
Medical Devices : Evidence and Research, 2016Co-Authors: Sunchai Theerapongpakdee, Thepakorn Sathitkarnmanee, Sirirat Tribuddharat, Siwalai Sucher, Maneerat Thananun, Duangthida NonlhaopolAbstract:BACKGROUND: The Lack's circuit is a co-axial Mapleson A breathing system commonly used in spontaneously breathing anesthetized adults but still requires high Fresh Gas Flow (FGF). The Lack-Plus circuit was invented with the advantage of lower FGF requirement. The authors compared the Lack-Plus and Lack's circuit for the minimal FGF requirement with no rebreathing in spontaneously breathing anesthetized adults. METHODS: This was a randomized crossover study. We enrolled 24 adult patients undergoing supine elective surgery, with a body mass index ≤30 kg/m2 and an American Society of Anesthesiologists physical status I-II. They were randomly allocated to group 1 (LP-L) starting with Lack-Plus then switching to Lack's circuit or group 2 (L-LP) (with the reverse pattern). After induction and intubation, anesthesia was maintained with 50% N2O/O2 and desflurane (4%-6%) plus fentanyl titration to maintain an optimal respiratory rate between 10 and 16/min. Starting with the first circuit, all the patients were spontaneously breathing with a FGF of 4 L/min for 10 min, gradually decreased by 0.5 L/min every 5 min until FGF was 2.5 L/min. End-tidal CO2, inspired minimum CO2 (ImCO2), mean arterial pressure, and oxygen saturation were recorded until rebreathing (ImCO2 >0 mmHg) occurred. The alternate anesthesia breathing circuit was used and the measurements were repeated. RESULTS: The respective minimal FGF at the point of rebreathing for the Lack-Plus and Lack's circuit was 2.7±0.8 and 3.3±0.5 L/min, respectively, p
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a clinical determination of optimal Fresh Gas Flow in a baby ear circuit
Journal of the Medical Association of Thailand Chotmaihet thangphaet, 2009Co-Authors: Sunchai Theerapongpakdee, Thanyathorn Phanpanusit, Duenpen Horatanaruang, Piyaporn Bunsangjaroen, Prapapan Limpkulwathanaporn, Maneerut Thananun, Duangthida NonlhaopolAbstract:Objective: Baby EAR circuit is a new modified enclosed afferent reservoir anesthetic breathing system for pediatric patients. By following His Majesty the King of Thailand’s self-sufficiency philosophy, the circuit is simple and made of low-cost and easy-to-find materials found in the operating room. This present study was to investigate clinical use of the circuit and to find the optimal Fresh Gas Flow in clinical setting. Material and Method: A prospective descriptive study was conducted in pediatric patients, weighed 5-20 kg, anesthetized for surgery. The Baby EAR breathing circuit was used for general anesthesia with endotracheal tube and control ventilation. Different Fresh Gas Flow of 3,2.5,2 and 1.5 liter per minute (LPM) was used consecutively. The authors recorded end-tidal carbon dioxide (EtCO2) and mean inspiratory carbon dioxide (ImCO2 ) while using Fresh Gas Flow at 3, 2.5, 2, and 1.5 LPM. EtCO2 of 35-45 mmHg and ImCO2 of < 6 mmHg were considered clinically acceptable. Results: Fifty patients were enrolled. Mean value (95% CI) of EtCO2 at Fresh Gas Flow rate of 1.5, 2, 2.5, and 3 LPM were 39.6 (39.2, 40.9), 36.7 (35.5, 37.8), 35.4 (34.3, 36.4), and 35.4 (34.3, 36.4) mmHg respectively. Mean value (95% CI) of ImCO2 at Fresh Gas Flow rate of 1.5, 2, 2.5, and 3 LPM were 4.0 (3.0, 4.9), 2.4 (1.7, 3.0), 1.8 (0.9, 2.6), and 1.3 (0.9, 1.7) mmHg respectively. Percentage of patients (95% CI) who had clinically acceptable EtCO2 and ImCO2 at Fresh Gas Flow rate of 1.5, 2, 2.5, and 3 LPM were 70% (56.2, 80.9), 92% (81.2, 96.8), 98% (89.5, 99.6), and 100% (92.9, 100) respectively. No patients had serious complications. Conclusion: Baby EAR circuit can be made economically and used safely for general anesthesia with control ventilation in pediatric patients weighing 5 to 20 kg at optimal Fresh Gas Flow of 3 LPM. Keywords: Anesthesia, EAR circuit, Pediatrics, Respiration, Ventilators, Mechanical
